How can I differentiate between gout and other forms of arthritis in a patient presenting with joint pain?

To differentiate between gout and other forms of arthritis in a patient presenting with joint pain, consider the following:

• Suspect Gout Based on Presentation:
  • Suspect gout in people presenting with rapid onset (often overnight) of severe pain, together with redness and swelling, in one or both first metatarsophalangeal (MTP) joints ¹.
  • Also suspect gout if tophi are present ¹.
  • Consider gout if there is rapid onset (often overnight) of severe pain, redness, or swelling in other joints, such as the midfoot, ankle, knee, hand, wrist, or elbow ¹.
  • For people presenting with chronic inflammatory joint pain, consider chronic gouty arthritis ¹.
• Assess for Other Conditions:
  • It is important to assess the possibility of septic arthritis, calcium pyrophosphate crystal deposition, and inflammatory arthritis in people presenting with a painful, red, swollen joint ¹.
  • If septic arthritis is suspected, refer immediately according to the local care pathway ¹,².
• Diagnostic Steps:
  • Take a detailed history and carry out a physical examination to assess symptoms and signs ¹.
  • Measure the serum urate level to confirm the clinical diagnosis, with a level of 360 micromol/litre (6 mg/dl) or more being indicative ¹.
  • If the serum urate level is below 360 micromol/litre (6 mg/dl) during a flare and gout is strongly suspected, repeat the measurement at least two weeks after the flare has settled ¹.
  • Consider joint aspiration and microscopy of synovial fluid if a diagnosis of gout remains uncertain or unconfirmed ¹.
  • If joint aspiration cannot be carried out or the diagnosis remains uncertain, consider imaging the affected joints with X-ray, ultrasound, or dual-energy CT ¹.
• Referral to Specialist Services:
  • Consider referring a person with gout to a rheumatology service if the diagnosis of gout is uncertain ¹,².